github.com/gopherd/gonum@v0.0.4/lapack/testlapack/dlarfx.go (about)

     1  // Copyright ©2016 The Gonum Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package testlapack
     6  
     7  import (
     8  	"fmt"
     9  	"testing"
    10  
    11  	"math/rand"
    12  
    13  	"github.com/gopherd/gonum/blas"
    14  	"github.com/gopherd/gonum/blas/blas64"
    15  )
    16  
    17  type Dlarfxer interface {
    18  	Dlarfx(side blas.Side, m, n int, v []float64, tau float64, c []float64, ldc int, work []float64)
    19  }
    20  
    21  func DlarfxTest(t *testing.T, impl Dlarfxer) {
    22  	rnd := rand.New(rand.NewSource(1))
    23  	for _, side := range []blas.Side{blas.Right, blas.Left} {
    24  		// For m and n greater than 10 we are testing Dlarf, so avoid unnecessary work.
    25  		for m := 1; m < 12; m++ {
    26  			for n := 1; n < 12; n++ {
    27  				for _, extra := range []int{0, 1, 11} {
    28  					for cas := 0; cas < 10; cas++ {
    29  						testDlarfx(t, impl, side, m, n, extra, rnd)
    30  					}
    31  				}
    32  			}
    33  		}
    34  	}
    35  }
    36  
    37  func testDlarfx(t *testing.T, impl Dlarfxer, side blas.Side, m, n, extra int, rnd *rand.Rand) {
    38  	const tol = 1e-13
    39  
    40  	// Generate random input data.
    41  	var v []float64
    42  	if side == blas.Left {
    43  		v = randomSlice(m, rnd)
    44  	} else {
    45  		v = randomSlice(n, rnd)
    46  	}
    47  	tau := rnd.NormFloat64()
    48  	ldc := n + extra
    49  	c := randomGeneral(m, n, ldc, rnd)
    50  
    51  	// Compute the matrix H explicitly as H := I - tau * v * vᵀ.
    52  	var h blas64.General
    53  	if side == blas.Left {
    54  		h = eye(m, m+extra)
    55  	} else {
    56  		h = eye(n, n+extra)
    57  	}
    58  	blas64.Ger(-tau, blas64.Vector{Inc: 1, Data: v}, blas64.Vector{Inc: 1, Data: v}, h)
    59  
    60  	// Compute the product H * C or C * H explicitly.
    61  	cWant := nanGeneral(m, n, ldc)
    62  	if side == blas.Left {
    63  		blas64.Gemm(blas.NoTrans, blas.NoTrans, 1, h, c, 0, cWant)
    64  	} else {
    65  		blas64.Gemm(blas.NoTrans, blas.NoTrans, 1, c, h, 0, cWant)
    66  	}
    67  
    68  	var work []float64
    69  	if h.Rows > 10 {
    70  		// Allocate work only if H has order > 10.
    71  		if side == blas.Left {
    72  			work = make([]float64, n)
    73  		} else {
    74  			work = make([]float64, m)
    75  		}
    76  	}
    77  
    78  	impl.Dlarfx(side, m, n, v, tau, c.Data, c.Stride, work)
    79  
    80  	prefix := fmt.Sprintf("Case side=%c, m=%v, n=%v, extra=%v", side, m, n, extra)
    81  
    82  	// Check any invalid modifications of c.
    83  	if !generalOutsideAllNaN(c) {
    84  		t.Errorf("%v: out-of-range write to C\n%v", prefix, c.Data)
    85  	}
    86  
    87  	if !equalApproxGeneral(c, cWant, tol) {
    88  		t.Errorf("%v: unexpected C\n%v", prefix, c.Data)
    89  	}
    90  }